The present invention relates to tone generation control programs for performing tone generating signal control in response to operation of keyboards to cause electronic keyboard instruments to electronically generate tones, and electronic keyboard instruments using such tone generation control programs. Particularly, the present invention concerns an improved tone generation control program which can be suitably applied to various types of electronic keyboard instruments, having different numbers of sensors provided at predetermined positions along the key strokes of individual keys for detecting depression of the keys, for performing tone generating signal control to allow each of the electronic keyboard instruments to accurately generate tones, and an electronic keyboard instrument using the improved tone generation control program. The present invention also relates to an electronic keyboard instrument using the tone generation program and a method for generating tone-generation controlling key-on and key-off signals according to a procedure corresponding to the tone generation program.
From U.S. Pat. No. 6,365,820, etc., there have been known electronic keyboard instruments which are constructed in imitation of natural keyboard-type musical instruments and electronically generate tones in response to player's operation on the keyboard. Namely, such electronic keyboard instruments, each including a keyboard to be operated by a human player as in natural musical instruments, generate tones in accordance with tones pitches and tone generation timing determined by player's operation on the keyboard. There haven been known two major schemes for detecting depressed states of the individual keys in the electronic keyboard instruments. The first scheme uses a first-type key operation detection device for generating detection signals of a plurality of positions, in response to depression of a key, via key-depression detecting sensors etc. provided at two predetermined points along the key stroke of each key; for convenience; this scheme will be referred to as a “two-make touch response switch scheme”. The second scheme uses a second-type key operation detection device for generating detection signals of a plurality of positions different from those in the first-type key operation detection device, in response to depression of a key, via key-depression detecting sensors etc. provided at three predetermined points along the key stroke of each key; for convenience, this scheme will be referred to as a “three-make touch response switch scheme”.
The above-mentioned two-make touch response switch scheme and three-make touch response switch scheme will be explained briefly with reference to FIG. 5. FIG. 5 is an enlarged fragmentary view schematically showing construction of keyboards in electronic keyboard instruments; namely, construction of keyboards in two electronic keyboard instruments employing the two-make touch response switch scheme (hereinafter also called “two-make construction”) and three-make touch response switch scheme (hereinafter also called “three-make construction”), respectively, are illustrated in the same figure to facilitate comparison between the two schemes. Keyboard 1 includes a plurality of white keys and a plurality of black keys; however, the construction will be explained here in relation to one of the white keys depicted at 11 in FIG. 5. Note that the other keys (other white and black keys) are constructed similarly to the key 11. The key 11 is pivotable downward by downward depressing operation depicted by a black arrow (representing the “depressing direction”) in the figure. For each of the keys, a sensor located at a predetermined highest depression position of the key will be referred to as an “a” sensor, a sensor located at a predetermined intermediate position will be referred to as a “b” sensor, and a sensor located at a predetermined lowest position will be referred to as a “c” sensor.
As will be understood from FIG. 5, the electronic keyboard instrument based on the two-make touch response switch scheme includes sensors placed at two, highest and lowest, depression positions corresponding to initial and full depression of the key (i.e., “a” and “c” sensors). Contact switches of the individual sensors placed in this manner are turned on/off in response to pivotal movement of the key 11, so that a current depressed state of the key 11 can be detected by the sensors. Then, a start and stop of audible generation (i.e., start of sounding and silencing or deadening) of a tone at a pitch assigned to that key 11 is controlled in accordance with the depressed state of the key 11 detected by the sensors. In addition to such control of the audible generation of the tone, velocity control of the tone may be performed by identifying a velocity of the depressing operation of the key 11 on the basis of a difference between times of detection by the two contact switches.
The three-make touch response switch scheme, which may be called an improvement over the two-make touch response switch scheme, includes sensors placed not only at the highest and lowest depression positions corresponding to the initial and full depression of the key but also at a predetermined intermediate position between the highest and lowest depression positions; namely, the electronic keyboard instrument based on the three-make touch response switch scheme includes the “b” sensor in addition to the “a” and “c” sensors. With the three-make touch response switch scheme that permits finer detection of the pivotal movement of the key 11 than the two-make touch response switch scheme, the human player can instruct re-generation of the tone by just returning the key 11 to the intermediate point without completely returning the key 11 to the initial depression position; in this way, it is possible to enhance the capability of the instrument to generate successive tones of a same note in response to successive depressing operation of the same key. Further, because the three-make touch response switch scheme permits more accurate detection of the depressing velocity of the key 11, finer velocity control can be performed.
Of the sensors shown in FIG. 5, the “b” sensor and “c” sensor can only detect when the key 11 has moved from a shallow depression position to a deep depression position. The “a” sensor, on the other hand, can not only detect when the key 11 has moved from the shallow depression position to the deep depression position but also detect when the key 11 has moved from the deep depression position back to the shallow depression position in response to key-releasing operation by the human player.
Generally, keyboards of electronic keyboard instruments are constructed on the basis of either the two-make touch response switch scheme or the three-make touch response switch scheme. In order to perform tone generating signal control in accordance with the keyboard construction actually employed (i.e., two- or three-make touch response switch scheme), it has been necessary to prepare in advance respective dedicated tone generation control programs for the two- and three-make touch response switch schemes and previously install a suitable one of the dedicated tone generation control programs in accordance with the actual construction of the keyboard. However, developing the separate tone generation control programs for the two- and three-make touch response switch schemes would significantly add to development cost. Further, any necessary change, addition, correction or the like has to be made separately to each of the tone generation control programs for the two touch response switch schemes, which would require extra time and labor. Furthermore, a sophisticated electronic keyboard instrument has recently been known, which has a structure to allow its component parts to be upgraded at any desired time, for example, after purchase of the instrument. When the keyboard in such a sophisticated electronic keyboard instrument is upgraded from the two-make touch response switch scheme to the three-make touch response switch scheme, there would arise a need to replace the tone generation control program for the two-make touch response switch scheme with the tone generation control program for the three-make touch response switch scheme (namely, reinstall the tone generation control program). Such program replacing operations would be very cumbersome, or the replacement of the tone generation control program itself tends to be completely forgotten.